Azo-coupled zinc phthalocyanines: Towards broad absorption and application in dye-sensitized solar cells

• Published in: Polyhedron Vol. 85; pp. 864 - 873
• Main Authors: Han, Mingliang, Zhang, Xuejun, Zhang, Xiaoxia, Liao, Chaoqiang, Zhu, Baiqing, Li, Qiaoling
• Format: Journal Article
• Language: English
• Published: OXFORD Elsevier Ltd 08.01.2015; Elsevier
• Subjects: Absorption spectra; Azobenzene; Chemistry; Chemistry, Inorganic & Nuclear; Crystallography; Dye-sensitized solar cells; Electrochemistry; Phthalocyanines; Physical Sciences; Science & Technology; LBJCLEGNYAILEU-UHFFFAOYSA-L; Dye-sensitized solar cells; CLPDMTSPYDVUQQ-UHFFFAOYSA-N; RTPZZUFHMKGMOB-UHFFFAOYSA-L; Electrochemistry; Absorption spectra; MDAXGYRAZLWOTB-UHFFFAOYSA-N; Phthalocyanines; Azobenzene; POLYMERS; DESIGN; PHOTOCHEMICAL PROPERTIES; ORGANIC-DYES; SUBSTITUENTS; DISPERSE DYES; AMINOTHIOPHENES; BETA POSITIONS
• ISSN: 0277-5387
• DOI: 10.1016/j.poly.2014.10.026

The design, synthesis, characterization, spectroscopic analysis, electrochemistry, thermal studies and TiO2 electrode tests of the four azo-coupled zinc phthalocyanines 7, 8, 10 and 11 reported. The new sensitizers incorporated azo dyes and Pcs directly by NN double bonds in single structures and showed remarkable absorptions. The synthesis of symmetrical azo-coupled zinc phthalocyanines (7, 8, 10 and 11) incorporating two spectrally complementary photogenerators (azo dyes and phthalocyanines) by NN double bonds in a single structure was described. The four sensitizers were fully characterized by Fourier Transform infrared spectroscopy, UV–Vis spectroscopy, proton nuclear magnetic resonance, mass spectrometry, elemental analyses, thermogravimetric analysis and cyclic voltammetry. All the azo-coupled phthalocyanines exhibited broad absorptions covering the range 300–800nm. The cyclic voltammetry studies indicated that the LUMO and HOMO energy levels of four synthesized azo-coupled phthalocyanines could ensure efficient electron injection and thermodynamically favorable dye regeneration. Thermal stability studies showed that the four sensitizers were stable above 200°C. The new compounds were tested in dye-sensitized solar cells and compound 8 showed the best photovoltaic performance, yielding 2.7% power conversion efficiency.